In real life, people usually use hand carts to transport luggage or cargo, etc., it's quite convenient. A common handcart usually comprises a draw rod, a bearing-board, and vehicle wheels mounted under the bearing-boards; by pulling the draw rod with the hand, the wheels will be dragged to roll, and the bearing-board will move, thus transporting luggage or cargo. There are two types of common handcart: the first type usually comprises a base board and four wheels mounted under the base board, this makes the whole handcart able to be parked steadily, and all the weight of the luggage and cargo is taken by the base board; the draw rod is mounted at the other side of the base board, and is used to pull the base board to move, the draw rod doesn't take the weight of the luggage/cargo, when pulling the handcart, you only need to pull horizontally at the draw rod, this type is usually used to transport heavy weight goods. But, this type of handcart can not be folded easily, and it is inconvenient for storage or empty load.
The second type of handcart can be folded, and two wheels are usually mounted under the base board, the draw rod is mounted at one side of the base board, the draw rod can be folded on the base board to make it convenient to reduce the handcart's volume for storage or empty load. But when transporting heavy weight goods, the draw rod needs to be tilted to make the base board raised up, and then the base board can be pulled to move, at that time, the fulcrum formed by the wheels and the hand which is pulling the draw rod will take all the weight, so this type of handcart is only used to transport light weight goods. If the weight is too heavy, the draw rod will be bent easily, and even be broken, and it's very laborious while pulling the handcart to move.
A couple of comments about the relevant patent literature, among the relevant patent literature, CN201272376Y and CN201249791Y are similar in high degree. At a glance, this handcart is similar to the above two types of handcarts, but they are very different.